1. Field of the Invention
The present invention relates to an air conditioner, and more particularly, to an air conditioner having an indoor device, an outdoor device, and a ventilation unit.
2. Description of the Related Art
In general, an air conditioner sustains indoor air to provide a comfortable environment to a human being and absorbs heat from indoor, emits heat to indoor, or enhances a clean degree of indoor.
The air conditioner is largely classified into an integral type and a separation type, and the separation type air conditioner includes an indoor device positioned at indoor and an outdoor device installed at a location other than indoor in which the indoor device performs air-conditioning.
When the outdoor device is installed in an outdoor device installation stand installed to protrude to the outside of a building, or is installed in a veranda, which is a portion of a building, the outdoor device exchanges heat by directly inhaling outdoor air and discharges again the outdoor air to outdoor, and when the outdoor device is installed in a building such as a commercial building, the outdoor device is installed in an outdoor device installation room formed in the building to exchange heat by inhaling outdoor air into the building and discharges the outdoor air to the outside of the building.
Nowadays, in order to provide more comfortable air to indoor, a ventilation unit for ventilating indoor air and outdoor air by discharging indoor air to the outside and inhaling outdoor air into indoor space is installed in the air conditioner.
In general, upon performing a heating operation, outdoor air is in a temperature lower than that of indoor air, and upon performing a cooling operation, outdoor air is in a temperature higher than that of indoor air and thus when the ventilation unit ventilates outdoor air and outdoor air, heating performance/cooling performance is lowered.
When a heat exchanger for exchanging heat of indoor air and outdoor air is installed in the ventilation unit, a temperature of outdoor air rises or falls by exchanging heat with indoor air while passing through the heat exchanger and the outdoor air is injected into indoor and thus a temperature difference between outdoor air injected into indoor space and indoor air exhausted to outdoor can be reduced and deterioration of heating performance/cooling performance due to ventilation can be minimized.
When the ventilation unit is installed in an outdoor device installation room together with the outdoor device, an outdoor air inhalation ventilating opening for inhaling outdoor air and an indoor air exhaust ventilating opening for exhausting indoor air should be each constructed in a building, a ventilation exhaust duct for communicating the ventilation unit and outdoor is disposed between the ventilation unit and an indoor air exhaust ventilating opening, and when an outdoor device installation room is small and narrow, a connection operation of the ventilation exhaust duct is not easy.
Further, when outdoor is in a low temperature, frost is generated in an outdoor device, the air conditioner delays generation of frost or performs a defrost operation for defrost, and when performing a defrost operation, indoor is not heated, and thus heating performance is lowered due to a defrost operation.